Multiobjective optimization means simultaneously finding a good solution that works for multiple measures of success.  Is Google currently using this idea to determine page rankings?  Can ELW reverse engineer Google’s search algorithms by assuming they are using these techniques?  The trick would be to figure out what Google wants to improve.  Obviously, Google makes money when searchers click on ads next to search results.  Directly optimizing search results to increase revenue would probably lead to crappy pages taking up the first few positions.  This would increase the number of people clicking on ads instead of search results.  I’m not so sure Google would do this, since the extra revenue may be at the cost of losing those customers next time.  The only alternative left is for Google to try to maximize long term revenue by maintaining the quality of organic search results.  This is a multiobjective optimization problem!

First, let me say that this is only speculative.  Anyone who has read my other articles can figure out what my basic view on Google are.  I suspect that what Google does is much less sophisticated than any theoretical optimization problem would allow.  Good optimization techniques are slow, and don’t scale well to anything near the size of Google.  It sure is lucky for the world of computer scientists that simple and fast ideas work so well.  Sometimes “dumb” solutions actually work better!

Forget everything you think goes into a search engine’s ranking algorithm for a minute.  How would you compare the quality of two different algorithms?  You need to actually put them into practice and look at the click-through data!  Which ranking components lead to the most clicks on the first few results?  Which bad ranking components lead people to enter a different query, or look at search results on the second and third pages before they find what they want?

I have done quite a bit of experimenting on this, and have developed a combined algorithm for improving search engine ranking algorithm quality by optimizing for positive click feedback.  Contact ELW if you have a few million dollars and want to give Google a serious run for their money!